The present inventions are related to systems and methods for transferring information, and more particularly to systems and methods for transferring information from a storage medium.
In a traditional storage device, information is longitudinally recorded on a magnetic storage medium. In a longitudinal recording scenario, data detection processes key on data transitions. As such, low frequency components (including any DC component) of the signal sensed from the magnetic storage medium does not convey information and may be eliminated. In addition, there is a desire to provide a high pass filter in a preamplifier associated with a data detection system to allow for fast write to read recovery.
In contrast to longitudinal recording where data detection keys on transitions, in newer perpendicular recording scenarios the magnitude of the field sensed from the magnetic storage medium carries information. In such a case, use of a high pass filter likely eliminates some information sensed from the magnetic storage medium. In addition, as disk format efficiency demands low coding overhead, the capability to provide for detecting low frequency components by means of RLL encoding is limited. In some cases, the aforementioned loss of low frequency energy has resulted in a lower signal to noise ratio in devices using perpendicular recording approaches. Prior data detection systems included the use of an error feedback signal derived from the detected bits to drive a spectrum mismatch compensation circuit. Such an approach may be used to preserve lower frequency information eliminated by the high pass filter, however, such an approach relies on DC and low frequency energy derived from detected data bits to drive the feedback error signal. In such an approach, latency becomes a major concern and ultimately limits any ability to obtain DC and low frequency energy.
Hence, for at least the aforementioned reasons, there exists a need in the art for advanced systems and methods for accessing information from a storage medium.